Safety, accuracy and reliability of operation are critical for electro-medical equipment. This article discusses the latest solutions that help install, calibrate and maintain these equipment
The most significant advances in the field of medicine have been in the technologies used to diagnose and treat patient. Biomedical equipment used in hospitals include numerous different types of electrodes, transducers, biomedical recorders and patient monitoring systems. We have come such a long way that instruments shown in sci-fi videos like Tricorders are now almost here. In fact, Qualcomm has launched a 10-million dollar competition called Qualcomm Tricorder X to motivate designers. Our point here is that as medical equipment advance, so should the test equipment that help design them.
Test equipment for medical electronics are usually used to calibrate, regulate, fine-tune or test electrical or electronic equipment that are used in a healthcare environment. Apart from use while designing the equipment, these can also be used for servicing, repair and other maintenance tasks.
Major differentiating factors for testing medical electronics
Since treatment given to the patients depends on the measurements by electro-medical instruments, calibrating and later maintaining this precision are of prime importance. Starting from the large X-ray equipment to the smaller patient monitors, all electronic equipment in a hospital need to be maintained as these work within extremely stringent conditions. In addition, electronic wheel-chairs, hearing-aids and surgical equipment are also expected to adhere to strict electro-medical requirements so that these do not interfere with other equipment. Safety, accuracy and reliability of operation are the critical factors.
“Medical device development is a complex process with quality being the highest concern. However, reducing development time is a pressure critical to establishing an early position in a very competitive market. To manage the quality concerns, agencies such as the Food and Drug Administration (FDA) have been established to help guide and enforce best practices for the development of safe and reliable devices. The rest is up to the engineers, to work within those constraints and meet all of the requirements in the most timely and cost-effective manner,” explains Satish Mohanram, technical marketing manager, National Instruments.
Electro-medical test equipment also need to adhere to standards like IEC 62353. The IEC 62353 is a standard for in-service and after-repair testing of medical electronic devices.
In the box on the next page, we have listed key factors that customers should look at when purchasing test equipment. Apart from those, validation and verification is a very important part of building a measurement and automation solution in the life sciences arena.
Measuring biological electrical phenomena with signal measurement systems is challenging. Electrical signals from the body are tiny microvolt pulses that signal a muscle response or a ‘firing’ neuron. Apart from being very small, these signals are also intermittent and hidden amongst other noise. This necessitates the need for a wide dynamic range, high-quality signal conditioning and storage capacity to store signals for a long duration with precision.
Boosting reliability and efficiency
Electro-medical test systems have been mostly custom-built rack-and-stack test benches, which are slowly becoming software-driven. Concepts such as hardware-in-loop and model-in-loop testing are gaining popularity as these approaches enable thorough testing of the medical equipment’s functionality. Tools such as LabVIEW and reconfigurable input/output hardware play a vital role in these closed-loop complex plant simulation and test scenario implementation.
Any test system that is used in the manufacturing and/or verification of a medical device must also be included in the validation process of that device.
“This means that the test code is subject to the same scrutiny with regards to development practices, change management and documentation as the firmware of the device. This brings a new constraint on the people designing their systems. They have the job of writing and building the test system. The PXI platform with LabVIEW software has been widely used as the test bench for verification and validation, and test cases are reused on the manufacturing line for product end-of-line testing,” explains Mohanram.
Improvements in minimally invasive techniques as well as drug delivery technologies have resulted in advances in imaging and navigation technologies.
“This will continue to improve diagnostic accuracy and also enhance surgical capabilities. Upcoming solutions should also incorporate bioinformatics, which can result in early and faster diagnosis, better prognosis and tailored therapies. Personalisation of such devices could help a lot, where individuals’ medical history and information could be available easily and at one place whenever needed,” adds T. Anand, managing director, Knewron.
After a medical device is designed and developed, it has to be approved before being marketed. What’s important to note is that medical device approvals are treated differently in different countries and controlled by the local authorities.
“For example, in European Union, requirements related to medical devices are illustrated in the form of directives. Medical devices, active implantable medical devices and in vitro diagnostic medical devices can be placed in European market only after they are CE marked. CE mark can be achieved by showing compliance to the applicable directives of European Union. Similarly, in USA, it is necessary to obtain the FDA clearance before placing medical devices into the market. In Canada, it is necessary to register certain medical devices with Health Canada before placing them in the market,” explains Kalyan Varma, country head-products, TUV Rheinland (India).
Another aspect is the growing significance of mechatronics in the field of medicine. The application of mechatronics in medical electronics has now risen from simple positioning systems to robotic surgical devices, and even surgery simulation systems based on haptics. Performing verification and validation is one approach to reduce the errors caused by the system. In order to measure how good the device is at avoiding or recovering from errors, a term called ‘mechatronics maturity’ is used. Virtual test instruments are also available, which allow designers to probe complete systems for all the signals from the sensors and actuators.
Just as electronics technology moves forward in leaps and bounds, all fields that depend on electronics also get the benefit of superior technology. Biomedical instrumentation is one area that is continuing to grow.
Anand shares a new innovation from Knewron: “We are working on design and development of an automated medicine vending machine, which perhaps is not a new concept for developed countries but has very high utility for a developing country like ours. Especially for rural areas, this could be extremely helpful. Availability of basic critical medicine and OTC drugs has been the pain area for a long time, and we believe that this solution may address the issue in a better way.”
Latest advances in medical technology have also enabled patients to access personal health information in real time, helping them to maintain their health. These devices should function perfectly at all times as the information provided by them is critical for the patient.
“A well-known Fortune 500 company that produces high-quality medical devices needed to perform comprehensive product life tests on its newest portable medical devices used for health monitoring. Specifically, they needed to measure reliability and longevity of the consumer product. The system needed to perform simultaneous tests on 30 units and generate sufficient data with the proper sample size so that design problems could be statistically differentiated from assembly problems or other anomalies”—explains a case study from National Instruments.
Precision is of paramount importance for the highly sophisticated machines that we see today—and quality of medical care would deteriorate if test equipment fail to guarantee efficient and safe operation of electro-medical devices.
“Upcoming solutions in electro-medical domain should focus on cost innovation since this would be the driving force for proliferation of such devices and services based on these solutions. Besides cost innovation, miniaturisation, accessibility and possibility to interlink with many other devices would be the most desired features,” adds Anand.
The author is a tech correspondent at EFY